Embodiments of the invention relate to testing procedures. More particularly, embodiments of the invention relate to the analysis of data collected in connection with testing pressure.
Electric generator stator bars are constrained from movement within slots in the stator by a wedge system. If the wedge system becomes loose, the stator bars can move relative to the slots. This relative motion contributes to bar insulation abrasion and potential bar failure via short to ground. Currently, although wedge systems are designed to engineering unit (pressure or force per unit length) constraints, wedge system tightness assessments cannot be related to those engineering design unit constraints for accurate assessment of required maintenance.
Two methods for semi-quantitative assessment of the tightness of a generator""s wedging system currently exist. The first is a modification of the Brinnell/Rockwell hardness test and employs rebound velocity of a spring-loaded pin or arm. The second is a technique that applies a multi-tap forcing function to a wedge and measures the absolute magnitude of the vibrational response in three discrete frequency bands below 1000 Hz.
Embodiments of the invention include methods for measuring pressure on a member in which the member is excited to create a current vibratory response in the member and the current vibratory response is detected. The current vibratory response is compared to at least one of a plurality of previously recorded vibratory responses of the member. The pressure on the member is then estimated based on the comparison of the current vibratory response to at least one of the plurality of previously recorded vibratory responses.
Embodiments of the invention include a system for measuring pressure on a member. The system having a vibration exciter for exciting the member to create a current vibratory response in the member, a sensor for detecting the current vibratory response, and a data storage device containing previously recorded vibratory responses. The current vibratory response is compared to at least one of the plurality of previously recorded vibratory responses, and the pressure on the member is estimated based on the comparison of the current vibratory response to at least one of the plurality of previously recorded vibratory responses.
Embodiments of the invention include a method for correlating vibratory response to pressure on a member. The method includes exciting the member while the member is subjected to a plurality of different pressures, detecting a vibratory response spectrum for each of the plurality of different pressures; and creating a spectrum-to-pressure correlation table. In the spectrum-to-pressure correlation table, the vibratory response spectrum for each of the plurality of different pressures is correlated to the pressure to which the member was subjected when the vibratory response spectrum was detected.
Embodiments of the invention include a system for correlating vibratory response to pressure on a member. The system has a vibration exciter for exciting the member while the member is subjected to a plurality of different pressures, a sensor for detecting a vibratory response spectrum in the member for each of the plurality of different pressures, and a processor for creating a spectrum-to-pressure correlation table. The system also has a data storage device for storing the spectrum-to-pressure correlation table. The spectrum-to-pressure correlation table contains at least the vibratory response spectrum for each of the plurality of different pressures correlated to the pressure to which the member was subjected when the vibratory response spectrum was detected.
These and other features of the invention will be readily apparent to those skilled in the art upon reading this disclosure in connection with the attached drawing figures.